Process for improving drying



Patented Apr. 9, 1940 PATENT OFFICE PROCESS FOR IMPROVING DRYING PROPERTIES OF OILS Theodore S. Hodgins, Royal Oak, Mich., assignor to Reichhold Chemicals, Inc.-, formerly Beck;

7 Koller & Company, Inc., Detroit, Mich.

No Drawing. Application July 17, 1939, Serial No. 285,001

4 Claims.

In common with the disclosure of my Patent No. 2,133,894 dated October 18, 1938, the present invention relates broadly to a process for improving the drying properties of naturally occurring 5 anti-oxidants.

According to the process claimed in said patent quantities with respect to the weight of the oil.

. Theopimum range in the case of the alkali was found to be.013- .050 part by weight of alkali to 100 parts by weight of the oil, and in the case of the acid reagent the range was .025-.050 part by weight of acid to 100 parts by weight of the oil being treated.

In my application Serial No. 240,858 filed November 16, 1938, now Patent No. 2,167,206 dated July 25, 1939, it was shown that similar results could be obtained by the use of an organic oxidizing agent such as benzoyl peroxide, and properly controlling the pH value of the solution .by the use of an acid or alkaline reagent in the proportion of approximately 1-5% by weight of the oil being treated.

The present application is specifically directed to the improving of oils using a definite quantity of a reagent which serves the dual function of an oxidizing agent and of a reagent for controlling the pH value of the solution. I have found that concentrated nitric acid fulfills this double function. The quantity of this acid employed may vary substantially within the range of .025-0.50% by weight of the oil, particularly good results 40 being obtainable when concentrated nitric acid in the proportion of about 0.20% by weight is employed.

Various types of oils containing naturally occurring anti-oxidants may be improved as to their drying properties by treatment in accordance with the present process, among which may acid within the limited range referred to above. The process efiectively removes the anti-oxidants (such as lecithin and kephalin) which are naturally occurring in these oils. The sludge containing the anti-oxidants and spent reagents I may be separated from the refined oil in any suit able manner, such "aisby filtering, centrifuging, orthe like, depending on the nature of the treating solution. a

I am aware that previous attempts have been 10 made to improve the drying properties ofoils by partially oxidizing the same, particularly by passing air'or other oxidizing gas through the body of the oil. My invention is not concerned with this type of oxidation. In such prior processes the oxi- 15 dation has taken place within the oil itself whereas according to my process only the anti-oxidants are eliminated, the oil being unoxidized. Also in such previous treatments temperatures above room temperature have been considered necessary whereas my process may be carried on to best advantage at substantially room temperature.

It has also been proposed totreat various oils with chemical reagents such as acids, alkalies and salts for the purpose of improving their qualtities, mi as for example for removing odors or bleaching the same, but to my knowledge no successful process has been carried out at room temperature wherein the anti-oxidants are removed by treatment at room temperature employing a small pre- 80 determined quantity of an oxidizing agent-which. also serves to control the acidity of the solution 4 within definite limits.

The invention will be more readily understood by reference to the following specific example. 86

Example Parts by weight Sunflower oil Concentrated nitric acid r 0.2 Water (not constant) 1.0to 10 The oil is preferably treated for one-half hour to two hours and may be mechanically agitated either by means of a stirrer or by blowing filtered air or an inert gas through the material, it being a of raw oils containing naturally occurring antioxidants, which comprises removing the antioxidants by treating the oil at substantially room temperature with intric acid, and maintaining the pH value of the materials undergoing treatment only slightly acid throughout the treatment by confining the quantity of nitric acid employed substantially within the range of .025-.50% by weight of the oil being treated,- continuing the treatment just until the refractive index begins to increase, then discontinuing the treatment and separating the treated oils from the other constituents.

2. A process as set forth in claim 1, wherein the quantity of nitric acid employed is approximately 0.20 by weight of the 011 being treated.

3. A process as set forth in claim 1, wherein the oil treated'is a member of a group consisting of linseed oil, soya bean oll, sunflower oil, perilla oil, rapeseed oil and oiticica oil.

'4. A process as set forth in claim 1, wherein the oil treated is sunflower oil.

. THEODORE S. HODGINS. 

